If You have the breathing apperater from the boomer quest as the key for the locked door is in the radiated water, so the breathing apperater helps you swim under water instead of going back up for air. The key is on the skeleton . hop this helps

Yes.... as "Foxxster" said. But there is 2 parts in the vault around the same area (look for the water pipes on the ceiling that's leaking water, those 2 parts you have to swim under the water to the end room (can't open any doors under there) but go to the end room look for the desk with the dead goul under it and search the goul you'll get the passphrase for the terminal that opens the door you have to go through, remember their are 2 of these underwater situations (done the same way) but the desk with the goul under it are in different spots in the end rooms, one desk is a sharp left when you get to the end room and the other is straight ahead and a tiny bit to the right, the first one is for the overseers office and the other one is for the armory. That is a pretty difficult vault to get through. Very Helpfull Walkthrough Links Fallout: New Vegas-Vault 34 Walkthrough-Part 1 - YouTube ------ Fallout: New Vegas-Vault 34 Walkthrough-Part 2 - YouTube .